The present technology relates to a display device capable of displaying a gray level image on a display section, imaging device capable of creating a gray level image of a subject, and a gray level voltage generation circuit.
In a display device such as a liquid crystal display device or an organic EL (Electro-Luminescence) display device, gamma correction is performed to correct the chroma and brightness of an image or the like to be displayed based on supplied image data. This gamma correction can be performed in a variety of manners. For example, gamma correction is performed by determining a gray level voltage for each gray level making up image data using a gray level voltage output from a gray level voltage generation circuit 400 shown in FIG. 15.
FIG. 15 illustrates an example of a gray level voltage generation circuit in related art. The gray level voltage generation circuit 400 shown in FIG. 15 includes resistance division circuits Rs1, Rs2 and Rs3 and resistance selection circuits 410 and 420. The resistance division circuits Rs1, Rs2 and Rs3 are also referred to as ladder circuits. The resistance selection circuits 410 and 420 select either one of the resistance division circuits Rs1, Rs2 and Rs3. In this configuration, one of the ladder resistors selected by the resistance selection circuits 410 and 420 is used to generate a gray level voltage for gamma correction.
Each of the resistance division circuits Rs1, Rs2 and Rs3 includes a plurality of resistors connected in series between gray level reference voltages VH and VL. In these resistance division circuits, a plurality of division points are formed between the gray level reference voltages VH and VL to generate different voltages. The resistances of the plurality of resistors are selected properly so that the voltages generated at the plurality of division points of the resistance division circuits achieve a desired gamma correction curve.
FIG. 16 illustrates examples of gamma correction curves achieved by the voltages at the division points of the resistance division circuits Rs1, Rs2 and Rs3. In the examples shown in FIG. 16, selecting the resistance division circuit Rs1 provides a gamma correction curve corresponding to γ(Rs1) shown in FIG. 16. Selecting the resistance division circuit Rs2 provides a gamma correction curve corresponding to γ(Rs2) shown in the same figure. Selecting the resistance division circuit Rs3 provides a gamma correction curve corresponding to γ(Rs3) shown in the same figure.
That is, image data is gamma-corrected in a desired manner by selecting one of the resistance division circuits Rs1, Rs2 and Rs3 and correcting the gray level voltage of each gray level of the image data using gray level voltages generated at the plurality of division points of the selected resistance division circuit.
In addition to the above, Japanese Patent Laid-Open No. 2003-223153 (hereinafter referred to as Patent Document 1) discloses a liquid crystal drive circuit that includes first and second resistance division circuits. The first resistance division circuit generates a gamma correction curve. The second resistance division circuit varies the voltage of the first resistance division circuit at a given division point.
In the liquid crystal drive circuit described in Patent Document 1, the voltage generated at the division point of the second resistance division circuit can be supplied to a given division point of the first resistance division circuit via a buffer adapted to reduce the impedance of the voltage. It is possible to achieve two different gamma correction curves by turning on and off this supply of voltage.